摘要
AIM: To investigate the relationship betweenhyposmotic membrane stretch and muscarinic receptoragonist-induced depolarization of membrane potentialin antral gastric circular myocytes of guinea-pig.METHODS: Using whole cell patch-clamp techniquerecorded membrane potential and current in singlegastric myocytes isolated by collagena se.RESULTS: Hyposmotic membrane stretch hyperpolarizedmembrane potential from -60.0mV±1.0mV to -67.9mV±1.0mV. TEA (10mmol/L), a nonselective potassiumchannel blocker significantly inhibited hyposmoticmembrane stretch-induced hyperpolarization. After KCIin the pipette and NaCI in the external solution werereplaced by CsCI to block the potassium current,hyposmotic membrane stretch depolarized the membranepotential from -60.0 mV±-1.0mV to -44.8 mV±2.3mV(P＜0.05), and atropine (1 pmol/L) inhibited thedepolarization of the membrane potential. Muscarinicreceptor agonist Carbachol depolarized membranepotential from -60.0mV±1.0mV to -50.3 mV±0.3mV(P＜0.05) and hyposmotic membrane stretchpotentiated the depolarization. Carbachol inducedmuscarinic current (Icch) was greatly increased byhyposmotic membrane stretch.CONCLUSION: Hyposmotic membrane stretchpotentiated muscarinic receptor agonist-induceddepolarization of membrane potential, which is relatedto hyposmotic membrane stretch-induced increase ofmuscarinic current.
AIM:To investigate the relationship between hyposmotic membrane stretch and muscarinic receptor agonist-induced depolarization of membrane potential in antral gastric circular myocytes of guinea-pig. METHODS:Using whole cell patch-clamp technique recorded membrane potential and current in single gastric myocytes isolated by collagenase. RESULTS:Hyposmotic membrane stretch hyperpolarized membrane potential from-60.0mV±1.0mV to-67.9mV± 1.0mV.TEA(10mmol/L),a nonselective potassium channel blocker significantly inhibited hyposmotic membrane stretch-induced hyperpolarization.After KCI in the pipette and NaCI in the external solution were replaced by CsCI to block the potassium current, hyposmotic membrane stretch depolarized the membrane potential from-60.0 mV±1.0mV to-44.8 mV±2.3mV (P<0.05),and atropine(1 μmol/L)inhibited the depolarization of the membrane potential.Muscarinic receptor agonist Carbachol depolarized membrane potential from-60.0mV±1.0mV to-50.3 mV±0.3mV (P<0.05)and hyposmotic membrane stretch potentiated the depolarization.Carbachol induced muscarinic current(I_(cch))was greatly increased by hyposmotic membrane stretch. CONCLUSION:Hyposmotic membrane stretch potentiated muscarinic receptor agonist-induced depolarization of membrane potential,which is related to hyposmotic membrane stretch-induced increase of muscarinic current.
基金
the National Natural Science Foundation of China,No.39860031.
